Yes, knowing your time of ovulation will help you plan contraception. To avoid pregnancy, you should abstain from unprotected sexual intercourse during your fertile days. Your fertile period starts about 4-5 days before ovulation, and ends about 24-48 hours after it. This is because sperm can live in your body for approximately 4 to 5 days, and the egg can live for 24 to 48 hours after being released. The most fertile time is the day of ovulation, and a day before it. As a precaution, we recommend that you avoid intercourse during the period starting 6 days before and ending 3 days after ovulation. See Avoiding Unwanted Pregnancy for more information.
You can configure 'My Calendar' to display the 'unsafe' days that may result in unwanted conception. The program performs all the necessary calculations automatically based on your time of ovulation, the lifespan of the egg and sperm, and possible variations in your cycle. 'My Calendar' shows the unsafe days marked with a 'stop sign':
Read Avoiding Unwanted Pregnancy for more information.
Although 'My Calendar' takes into account possible variations in your cycle, there is no 100% guarantee of safety. This is because the length of the menstrual cycle and your time of ovulation can vary from one cycle to the next due to a number of factors, such as stress, illness, diet, or increased physical activity.
To ensure that the fertility chart generated by 'My Calendar' is accurate, you need to keep the program updated with the latest information about your menstrual cycle. You can further reduce the chances of conception by combining the use of 'My Calendar' with other methods of contraception, such as spermicides, condoms, or diaphragms.